Mechanically-decoupled actuation for robotic catheter system

ABSTRACT

For robotically operating a catheter, a medical catheter is controlled by rotation of the catheter as well as steering in one or more planes of a distal end of the catheter. To robotically rotate the catheter, a handle is rotated. The steering is performed separately using one or more knobs on the handle. The rotation of the handle complicates the robotic control of the knob. A mechanical decoupling is used so that rotation of the handle maintains the position of the knob relative to the handle. Gearing or transmission is used to avoid independent control of the knob and handle rotation. In an alternative or additional approach, the handle may be robotically controlled while also guiding the catheter shaft spaced away from the handle, allowing fine-tuned control of the catheter at the access point to the patient.

RELATED APPLICATION

The present patent document claims the benefit of the filing date under35 U.S.C. § 119(e) of Provisional U.S. Patent Application Ser. No.62/877,622, filed Jul. 23, 2019, which is hereby incorporated byreference.

BACKGROUND

The present embodiments relate to robotic control of a medical catheter.One example medical catheter is an intra-cardiac echocardiography (ICE)catheter, which is used for cardiac interventional and diagnosticprocedures. ICE is able to provide close feedback of anatomicalstructures and tools during a surgical procedure.

One major challenge ICE and other interventional catheterization posesfor the operating interventionalist is the difficult cathetermanipulability. The ICE catheter is moved in a coordinated fashion withan interventional catheter. The operator manipulates multiple degrees offreedom simultaneously to achieve a desired pose as well as manages thecoordination. A robotic system that controls the degrees of freedom(DOFs) of an ICE catheter may reduce the cognitive strain on the user.

One commercially-available robotic system for ultrasound cathetermanipulation is the Stereotaxis Vdrive system. The mechanical design ofthis system controls only a limited number of degrees of freedom of theICE catheter. For example, the precise control of the orientation of thecatheter, which is necessary for appropriate imaging, may not beprovided. Additionally, all motions are done at the handle, far from theinsertion point, failing to account for the possibility of catheterbuckling. Another proposed, automated system for a handheld ICE catheterhas a large footprint and may be difficult to sterilize, making itunusable in a clinical setting

SUMMARY

By way of introduction, the preferred embodiments described belowinclude methods, systems, and robots for robotically operating acatheter. A medical catheter is controlled by rotation of the catheteras well as steering in one or more planes of a distal end of thecatheter. To robotically rotate the catheter, a handle is rotated. Thesteering is performed separately using one or more knobs on the handle.The rotation of the handle complicates the robotic control of the knob.A mechanical decoupling is used so that rotation of the handle maintainsthe position of the knob relative to the handle. Gearing or transmissionis used to provide independent control of the knob and handle rotation.In an alternative or additional approach, the handle may be roboticallycontrolled while also guiding the catheter shaft spaced away from thehandle, allowing fine-tuned control of the catheter at the access pointto the patient.

In a first aspect, a robotic catheter system includes a first motorconfigured by first gearing to rotate a catheter about a longitudinalaxis. The robotic catheter system also includes a second motorconfigured by second gearing to rotate a first knob of a handle of thecatheter. Third gearing connects between the first motor and the secondmotor so that the rotation of the catheter about the longitudinal axisby the first motor rotates the second motor to rotate the first knob.

In one embodiment, the first and second motors are servo motors. Inanother embodiment, a catheter handle housing and a base housing areprovided. The first and second motors are in the base housing. The firstand second gearing are in the catheter handle housing. The base housingis less than 16 inches long, 12 inches high, and 6 inches wide. Asanother embodiment, an arm connects with the base. The arm is jointedand connects to an access point housing configured to hold the catheteraway from the handle at a point of entry into a patient. The basehousing may have a second knob configured to adjust a position of thefirst and second motors relative to the base.

In another embodiment, the first knob comprises an anterior-posterior ora left-right knob for steering a distal end of the catheter. In afurther embodiment, the first knob is rotatable relative to the handleand about the longitudinal axis. The third gearing is configured so thatthe first knob maintains a position relative to the handle while thehandle rotates with the rotation of the catheter while the second motoris not activated.

In yet another embodiment, the first gearing includes a first gearmatable with a second gear. The second gear extends around the handle sothat rotation of the first gear by the first motor causes rotation ofthe second gear about the longitudinal axis.

For the third gearing, the third gearing including a gear with teetharound a cylindrical housing for the second motor according to oneembodiment. Rotation of the first motor rotates the cylindrical housingand the second motor therein. In a further embodiment, the second motoris offset from a longitudinal center of the cylindrical housing. Thesecond gearing includes a first shaft at the longitudinal center of thecylindrical housing so that the rotation of the cylindrical housingrotates the second motor about the longitudinal center.

For an embodiment with multiple knobs on the handle of the catheter, athird motor is within the cylindrical housing. Fourth gearing connectsthe third motor with a second knob of the handle. The fourth gearingincludes a second shaft at the longitudinal center of the cylindricalhousing. The first shaft is nested and rotatable independently of thesecond shaft.

In a second aspect, a method is provided for robotically operating acatheter. A first gear linked to the catheter is rotated so that therotating of the first gear causes a handle of the catheter to rotateabout a longitudinal axis of the handle. The rotation of the first gearis transmitted to a second gear so that rotation of the second gearcauses rotation of a third gear linked to a knob of the handle.

In one embodiment, rotating the first gear includes rotating the firstgear with a first motor. A second motor is configured to rotate thethird gear. The transmitting includes transmitting where the rotation ofthe third gear is from rotation of the second gear and not powered bythe second motor. In a further embodiment, the transmitting includesrotating a motor housing of the second motor where the second motor ismounted off-center in the motor housing. In another further embodiment,the third gear is rotated by the second motor independently of therotating of the first gear. The rotating the third gear is nottransmitted to the first gear.

In one example use, a base is positioned relative to a patient. Thehandle is positioned in a handle housing where the first gear is withinthe handle housing and connects with the base through a motor shaft. Aposition of the handle housing is adjusted relative to the base. Therotating then occurs after the adjusting.

In a third aspect, a system is provided for guiding a catheter. A handlehousing is configured to hold a handle of the catheter. The handlehousing has a first gear to rotate the handle and a second gear torotate a first knob on the handle. A base is connectable with the handlehousing so that the first and second gears are driven from the base. Anaccess point housing is configured to hold a shaft of the catheter awayfrom the handle. The access point housing is configured to adjust anangle of the shaft relative to the handle.

In one embodiment, a transmission in the base mechanically decouplesactuation of the first gear from the second gear. The transmissionincludes a third gear on a first shaft with the first gear. The thirdgear links to a fourth gear on a housing of a first motor linked to ashaft with the second gear so that rotation of the first gear causesrotation of the third gear, which causes rotation of the housing so thatthe second gear rotates, allowing the first knob to maintain positionrelative to the handle. In a further embodiment, a fifth gear connectswith and between the third gear and the fourth gear.

In yet another embodiment, an arm with one or more joints connects thebase to the access point housing. The access point housing includes oneor more motors for adjusting the angle.

The present invention is defined by the following claims, and nothing inthis section should be taken as a limitation on those claims. Featuresof one aspect or type of claim (e.g., method or system) may be used inother aspects or types of claims. Further aspects and advantages of theinvention are discussed below in conjunction with the preferredembodiments and may be later claimed independently or in combination.

BRIEF DESCRIPTION OF THE DRAWINGS

The components and the figures are not necessarily to scale, emphasisinstead being placed upon illustrating the principles of the invention.Moreover, in the figures, like reference numerals designatecorresponding parts throughout the different views.

FIG. 1 is a block diagram of one embodiment of a medical ultrasoundsystem for imaging with an ICE catheter;

FIG. 2 illustrates one embodiment of a robotic system for guiding acatheter;

FIG. 3 illustrates gearing according to one embodiment for guiding acatheter;

FIG. 4 is a flow chart diagram of one embodiment of a method forrobotically operating a catheter; and

FIG. 5 illustrates positioning of a base for robotically guiding acardiac catheter, such as an ICE catheter.

DETAILED DESCRIPTION OF THE DRAWINGS AND PRESENTLY PREFERRED EMBODIMENTS

A compact, sterilizable robotic catheter manipulator is provided forgeneral-purpose access points. The manipulator includes mechanicallydecoupled actuation of handle rotation and knob-based manipulation.Commercially-available catheter systems are robotized in a clinicalsetting. In one embodiment, two sets of motion transmission setups areprovided. The first, placed at the catheter handle, provides rotation ofthe handle, and control of the knobs that cause articulation of theflexible catheter body. The second is placed around the flexiblecatheter body itself and is placed near the insertion point in thepatient. This second, optional, setup provides translation and rotationof the catheter while limiting buckling caused by friction from theinsertion sheath. The end-effector of the medical device can beprecisely positioned because the first setup can be used for largervertical, yaw, and for-aft adjustments while an arm supporting thesecond setup may be moved for finer translational and angularadjustments.

Due to difficulties posed by control of a continuum manipulator such asan ICE catheter, the rotation of the catheter body is mechanicallydecoupled from the rotation of the knobs. The degrees of freedom forcontrolling the catheter are mechanically decoupled. Since the knobmotions are mechanically decoupled from the whole-body rotation, thecontrol effort is not burdened and can focus on more precise positioningof the catheter's sensor or of some other medical instrument.

The base of the device, which includes the motors, motor drivers, andadjustable degrees of freedom, is general purpose in that any devicethat can be fitted with an appropriate transmission system may be usedwith the base. The adjustable degrees of freedom and compactness of thebase allow for surgeries at different access points (e.g., femoral,radial, or jugular) and precise alignment of the medical instrument,such as alignment of an ICE catheter with a sheath. The base is easilyattached to the operating table or to another mobile table. Theposability of the modular base allows for precise alignment of thecatheter with the sheath. A plastic interface between the base and atransmission holding the catheter handle allows for the base to remainsterile so that the entire base is reusable and does not need to becleaned.

The robotic system fits a standard, commercially-available ICE catheter,such as those in the Acunav family of catheters from Siemens. Thesterile, modular robotic system provides for full-DOF robotic control ofan ICE catheter. This system may be used for any kind of catheter orflexible medical instrument for insertion into a patient, including butnot limited to bronchoscopes, flexible endoscopes, trans-thoracicechocardiography probes, trans-esophageal echocardiography probes,cardiac catheters for intervention (i.e., with medical tool forinteraction with tissue of the patient), and any other type of catheter.This system may be used with a more-integrated system, in which themotion-driving elements and the imaging device are all integrated intoone compact setup at production, as opposed to the embodiment describedhere, in which the imaging instrument and the robotic system are broughttogether at the time of use. Different methods for gripping and holdingthe catheter, for setting up the whole system, and/or for providingmotion transmission may be used.

FIG. 1 shows an example medical ultrasound system for ICE. This examplemedical ultrasound system uses the ICE catheter 12, which may berobotically controlled. The medical ultrasound system includes the ICEcatheter 12, a beamformer 24, an image processor 26, and a display 28.Additional, different, or fewer components may be provided, such asproviding just the catheter 12. The catheter 12 releasably connects withthe imaging system.

The ICE catheter 12 includes an array 14 of elements 16 for imagingwithin a shaft or housing 20 having a tip 32, electrical conductors 22,steering wires 30, and a handle 21. Additional, different, or fewercomponents may be provided, such as radio opaque markers, ablationelectrodes, lens, needle guide, or ports. In other embodiments, thecatheter 12 is an ablation catheter or interventional catheter ratherthan an imaging catheter.

The shaft housing 20 is PEBAX, nylon, polymer, or other flexiblematerial. The shaft housing 20 is formed around the array 14 and otherparts extending from the handle 21 and insertable into the patient. Theshaft housing 20 is configured for insertion into a circulatory systemof a patient. For example, the distal tip 32 of the catheter 12 includesa more flexible portion covered by the shaft housing 20 for movingthrough the circulatory system. Steering wires 30 connected to the shafthousing 20 or parts (e.g., anchors) within the housing 20 are configuredto guide the shaft housing 20 within the circulatory system.

The array 14 is positioned within the catheter 12. The array 14 may fitwithin 10 French, 3.33 mm, 12.5 French, or another diameter catheter 12.The array 14 is at a distal end or tip 32 of the catheter 12, such asbeing within 20 mm of an end of the tip 32 or a beginning of a flexibletip portion. The array 14 may have any position within the catheter 12that results in the array 14 being within the patient during use of thecatheter 12 for imaging.

The transducer array 14 is used for ultrasound imaging. The imagesassist in diagnosis, catheter guidance, needle guidance, ablationguidance, placement, and/or needle puncture. The array 14 scans in afield of view 18 in a plane perpendicular to the emitting face. Thepatient within the field of view 18 may be imaged using the array 14.

Electrical conductors 22 connect the elements 16 of the array 14 to thebeamformer 24. The conductors 22 are cables, coaxial cables, traces onflexible circuit material, wires, wire jumpers, combinations thereof,and/or other now known or later developed conductor.

The beamformer 24 includes a plurality of channels for generatingtransmit waveforms and/or receiving signals. Relative delays and/orapodization focus the transmit waveforms or received signals for formingbeams and setting a focal location. The beamformer 24 connects with theconductors 22 for applying waveforms for imaging with the array 14 andreceiving signals. For imaging, the beamformer 24 selects an apertureincluding one, some, or all of the elements 16 of the array 14. Forscanning, the beamformer 24 electronically focuses along the azimuthdirection. A plurality of scan lines using an aperture is scanned.During receive operations, the focus may vary as a function of depth(i.e., dynamic focusing).

The image processor 26 is a detector, filter, processor, applicationspecific integrated circuit, field programmable gate array, digitalsignal processor, control processor, scan converter, three-dimensionalimage processor, graphics processing unit, analog circuit, digitalcircuit, or combinations thereof. The image processor 26 receivesbeamformed data and generates images on the display 28, which is adisplay screen.

The steering wires 30 of the catheter 12 are used to position the array14 (and/or medical instrument) relative to the patient. The steeringwires 30 are cables, tendons, or other structure for transferring pushand pull force from the handle 21 to a portion of the catheter 12 withina patient, such as to the distal end or the tip 32. Any material may beused, such as plastic, fiberglass, or metal. Any number of steeringwires 30 may be used, such as three or four wires. For example, three orfour steering wires 30 offset from the center in an equal spacing aboutthe center or longitudinal axis may be used to steer along twoperpendicular planes. The steering wires 30 run through the elasticmaterial of the catheter body or shaft housing 20 to the distal end andare arranged in a circular fashion around a central channel, whichprovides sufficient space for the ultrasound transducer cable orconductors 22 to be guided through. The relative force between thesteering wires 30 causes the catheter 12 to bend. Any now known or laterdeveloped arrangement of steering wires 30 may be used.

In one embodiment, one knob 29 is provided for controlling the bend ofthe distal end in one plane. Two steering wires 30 connect with the knob29, so rotation of the knob 29 causes a change in relative pressure orforce on the steering wires 30. In another embodiment, two knobs 29 areprovided. One knob 29 (e.g., AP knob) is for bending in one plane, suchas an anterior-posterior (AP) plane, and another knob 29 (e.g., RL knob)is for bending in a perpendicular plane, such as a right-left (RL)plane.

The knob 29 rotates to steer. The knob 29 rotates about a longitudinalaxis of the handle 21 and/or catheter 12. For example, the knob 29 is acylinder or ring on the outer housing of the handle 21 for rotationabout the axis in either direction to steer. In other examples, the knob29 rotates around an axis perpendicular to the longitudinal axis of thehandle 21. Alternatively, a slider or lever is provided as the knob 29for steering.

The steering wires 30 control the bend at a distal end of the catheter12. The bend may be at a portion of the catheter 12 adjacent to thedistal end or tip 20, such as providing for the array 14 to be spacedfrom the handle 21 by the bend. For example, the steering wires 30 areanchored to the shaft housing 20, transducer array 14, or a rigid insertor anchor near the distal end to cause the bend. The elastic body orshaft housing 20 may be bent along its principal axes by applyingtension to the attached steering wires 30. Using motors instead ofuser-based rotation of two knobs for two planes allows for only threesteering wires 30 for forming the bend. Four steering wires 30 withmotor-based control may be used, such as where the handle 21 is designedfor manual operation.

The handle 21 includes a housing and user input in the form of one ormore knobs 29 (see knob 40 of FIG. 3). The handle 21 is shaped and sizedfor handheld guidance or use of the catheter 12. For example, the handle21 is cylindrical with grips to be used by one hand of a surgeon. Thehandle 21 has a single housing made of one or more parts. The housingconnects with the shaft housing 20 of the catheter 12 and with a cableor cables for power and communications. In alternative embodiments, thehousing is shaped for use with a robotic system rather than handheldguidance.

For robotic guidance, the catheter handle 21 is placed in an externalactuation stage. The actuation stage forms a motor housing. Rather thanhandheld use, the actuation stage provides control for rotation,steering, and/or translation to be automated. The operator is then ableto tele-operate the catheter 12 from a remote console, or a high-levelmotion planning algorithm may be used to generate spatial trajectoriesfor the catheter tip 32.

A controller controls the robotic guidance. The controller is aprocessor, application specific integrated circuit, integrated circuit,digital signal processor, field programmable gate array, or othercontrol device for controlling the motors of the robotic system. Thecontroller is configured by design, hardware, and/or software to steerthe catheter 12 using the user-based or other controls of the catheter12, such as the handle 21 for rotation about a longitudinal axis of thecatheter 12 and/or for translation along the longitudinal axis and oneor more knobs 29 for steering (i.e., bending) the distal end.

FIG. 2 shows a system for guiding the catheter 12. The system is arobotic catheter system for rotating and/or steering the catheter 12.The system includes a base 34, a catheter handle housing 33 (carriage),an access point base 38, an access point guide 39, and an arm 36.Additional, different, or fewer components may be provided. For example,the arm 36, access point base 38, and access point guide 39 are notprovided. As another example, the base 34 and the catheter handlehousing 33 are combined into one housing or device.

Each of the parts has a housing. The housings are plastic, metal, resin,silicone, or other material.

The catheter handle housing 33 is configured to hold the handle 21 ofthe catheter 12. Any part of the handle 21 may be held, such assurrounding 50-90% of the outer surface of the handle 21. In oneembodiment, the catheter handle housing 33 is a clam-shell shape withtwo halves. A hinge may be provided. Alternatively, the handle 21 isplaced in a lower half, and then the upper half is placed over the lowerhalf and latched to the lower half. Other arrangements, such as havingtwo or more rings to hold the handle 21, may be used.

The cables with or without an end of the handle 21 may extend out of thecatheter handle housing 33 when the handle 21 is positioned in thecatheter handle housing 33. The shaft housing 20 with or without anotherend of the handle 21 may extend out of the catheter handle housing 33when the handle 21 is positioned in the catheter handle housing 33. Theknob 29 or knobs 29 are within or at least partly within the catheterhandle housing 33.

Once positioned, one or more parts, such as rubberized or coated parts,form a pressure fit with the handle 21. For example, studs or one ormore rings contact the handle 21 and are movable (e.g., rotatable)within the catheter handle housing 33. A separate set of studs or a ringcontacts each knob 29 and are independently moveable (e.g., rotatable)within the catheter handle housing 33. As shown in FIG. 3, gears 41, 42,43 connect with each of the rotatable parts. For the handle 21, the gear43 is a circular gear surrounding and directly or indirectly contactingthe handle 21. For the knobs 29, 40, knob gears 41, 42, respectively,are circular gears surrounding and directly or indirectly contacting theknobs 29, 40. The gears 41-43 are bevel gears, but flat or straightgears or gears with tracks on the side of a disc shape may be used. Thegears 41-43 in the catheter handle housing 33 provide for drivenrotation of the handle 21 and/or the knobs 29, 40.

The catheter handle housing 33 also includes gears 44, 45, and 51 formating with and rotating the gears 41-43, respectively. The gears 44,45, and 51 are bevel gears, but flat or straight gears or gears withtracks on the side of a disc shape may be used.

The gears 44, 45, and 51 and gears 41-43 form sets of gearing in thecatheter handle housing 33 for transmitting force from the base 34 tothe handle 21 and knobs 29, 40. This gearing is used to control thecatheter robotically, such as the gearing of gears 44 and 41 and/or ofgears 45 and 42 being for operating the anterior-posterior and/orleft-right knobs 29, 40, respectively, for steering a distal end of thecatheter 12. To steer, the knobs 29 and/or 40 are rotated relative tothe handle 21, such as about the longitudinal axis of the handle 21, bythe gearing.

Referring to FIGS. 2 and 3, the base 34 includes the housing around oneor more motors 47, 48, and 53. The motors 47, 48, and 53 are within thebase 34. The motors 47, 48, and 53 include shafts 46 and 52 for drivingthe gearing in the catheter handle housing 33, allowing for roboticmanipulation of the catheter handle 21 and knobs 29, 40.

The housing of the base 34 has any size and shape. In one embodiment,the housing is prismoid, such as having six sides. The size and shapeallow for placement on or by a table on which the patient lies. Forexample, the housing of the base 34 is less than 16 inches long, 12inches high, and 6 inches wide. FIG. 5 shows an example with the base 34sized and shaped to be placed on a table between their legs of thepatient 70. This modular base 34 allows for placement at any desiredposition and orientation. The adjustable degrees of freedom andcompactness of the base 34 allow for surgeries at different accesspoints (e.g., femoral, radial, or jugular) and precise alignment of thecatheter 12 with the sheath at the access point in the patient 70. Thebase 34 may be attached to the operating table or another table bymagnets at the bottom (either a permanent magnet switch orelectromagnets). Gravity, suction cups, latches, and/or other attachmentdevices may be used. Larger height, width, and/or length may be used.

Referring again to FIGS. 2 and 3, the base 34 connects with the catheterhandle housing 33. The connection is through the shafts 46, 52, 58. Aplastic or other transmission may be used to transfer force from themotors 47, 48, 53 to the gearing (i.e., to gears 44, 45, 51 and thusgears 41, 42, and 43, respectively). The rotations, including speed,direction, and amount, of the handle 21 and knobs 29, 40 are driven fromthe base 34.

In one embodiment, the base 34 connects to the gearing through a plasticinterface of a sterile bag. The sterile bag includes one or more holesfor the shafts 52 and 58. The catheter handle housing 33 and accesspoint housing 39 are outside of the sterile bag while the base 34, arm36, and access point base 38 are in the sterile bag, allowing re-usewith less cleaning and avoiding discarding of expensive parts. Since allelectronics in the base 34 are kept sterile in a procedure, the base 34and electronics may be reused without cleaning. Since all parts notinside the bag are plastic or metal (i.e., the catheter handle housing33 and gearing inside the catheter handle housing 33), these parts maybe easily cleaned and reused.

The base 34 may include a rack holding the motors 47, 48, and 53 withinthe housing. The rack allows for shifting of position of the motors 47,48, and 53 relative to the housing. One or more knobs 35 provideadjustment of the rack, resulting in shift of an interface plate 59,which interfaces with the catheter handle housing 33. The knobs 35 arerotatable but may be levers or sliders. In alternative embodiments, therelative position is set by hand with an electromagnetic brake to lockthe position.

The interface plate 59 includes holes for the shafts 52 and 58 formounting on, connection to, or fitting with the gearing in the catheterhandle housing 33. The knobs 35 connect through gears, rack-and-pinion,belts, or other mechanical linkage to adjust a position of the motors47, 48, and 53 relative to the base 34. For example, the height andfore-aft position of the base interface 59 may be manually adjustedusing the two knobs 35 on the back or other location. The yaw of thebase may be adjusted either by positioning the base differently on thetable or by the pivot at the interface plate 59.

In one optional embodiment shown in FIGS. 2 and 3, an arm 36 extendsfrom the base 34. The arm 36 includes any number and/or type of joints.For example, four links with three elbow joints are used. The arm 36latches to or is formed as part of the base 34. Other connections to thebase 34 may be used. Alternatively, the arm 36 mounts to the table orother device and is not connected directly to the base 34. The arm 36 ismetal, rubber, fiberglass, plastic, and/or resin. The arm 36 may changeposition by manual adjustment. Alternatively, servo motors underelectrical control adjust one or more joints. Any number of degrees offreedom may be provided.

The arm 36 supports the access point housing 39 with or without anaccess point base 38. The access point base 38 may include motors andgearing for moving an orientation (rotation) and/or position(translation) of the access point housing 39. The access point housing39 holds the catheter 12, such as the shaft housing 20, at the accesspoint or entry point into the patient. For example, the shaft housing 20extends through an aperture formed by the access point housing 39, whichis elongated to assist in preventing buckling.

The arm 36 provides an initial positioning and orientation of the accesspoint housing 39 away from the handle 12 of the catheter and away fromthe base 34. The position and/or orientation of the access point housing39 may be further adjusted in three dimensions using the poseable arm 36in order to achieve the desired end-effector angle. The access pointbase 38 may manipulate the flexible catheter 12 itself, providing moredirect control of the flexible catheter body or shaft housing 20 nearits insertion point. This control or manipulation of the position andangle by the access point may reduce the chance of the catheter 12buckling when pushed, pulled, or rotated in relation to the insertionsheath.

Referring to FIG. 3, the base 34 houses the motors 47, 48, and 53. Themotors 47, 48, and 53 are servo motors, rotational motors, linear motors(e.g., linear magnetic motors), or other electric, pneumatic, orhydraulic motors for rotating the shafts 46, 58, and 52. Alternatively,gearing, clutch, and/or transmission is used to apply force from onemotor to multiple shafts. In order to keep the electronics sterile, thecontroller and motors 47, 48, and 53 are spaced away from the catheter12 by being positioned in the base 34.

One motor 53 rotates the shaft 52. Using the gearing of gears 51 and 43,the shaft rotation causes rotation of the gear 43, which rotates theentire catheter handle 21 within the catheter handle housing 33. Thegear 51 is driven to rotate by the shaft 52 from the motor 53. By matingwith the gear 43, the rotation of the gear 51 causes rotation of thegear 43 extending around the handle 21. The rotation of the handle 21 isabout the longitudinal axis of the catheter handle 21 and the catheter12.

To operate the knob 29 (e.g., RL knob), the motor 48 connects to theknob 29 through gearing. A motor shaft connects to and rotates a gear,which mates with a gear on the shaft 58. The shaft 58 rotates the gear44, which mates with and rotates the gear 41. The gear 41 surrounds theknob 29 and causes the knob 29 to rotate. The knob 29 rotates relativeto the handle 21. When the handle 21 is not rotating, any rotation ofthe knob 29 causes steering by the steering wires 30. When the handle 21is rotating due to the motor 53, additional rotation applied to the knob29 by the motor 48 causes steering by the steering wires 30.

No additional or additional motors are provided. In the embodiment ofFIG. 3, the motor 47 is provided. To operate the knob 40 (e.g., APknob), the motor 47 connects to the knob 40 through gearing. A motorshaft connects to and rotates a gear, which mates with a gear on theshaft 46. The shaft 46 rotates the gear 45, which mates with and rotatesthe gear 42. The gear 42 surrounds the knob 40 and causes the knob 40 torotate. The knob 40 rotates relative to the handle 21. When the handle21 is not rotating, any rotation of the knob 40 causes steering by thesteering wires 30. When the handle 21 is rotating due to the motor 53,additional rotation applied to the knob 40 by the motor 47 causessteering by the steering wires 30.

In one embodiment, the shaft 46 is nested in the shaft 58. The shaft 58is hollow. The shaft 46, with or without ball bearings, is positionedinside the shaft 58. In other embodiments, the shaft 58 is nested in theshaft 46. Alternatively, a transmission is used to control force fromone shaft to the different gears 44, 45.

The motors 47, 48 control the catheter 12 bending through control of theamount and direction of rotation of the knobs 29, 40. To actuate thebending of the catheter 12 by tendons or steering wires 30 running alongthe catheter 12, the motors 47, 48 apply tendon pulling or pushingforces by knob rotation. To steer, the knobs 29, 40 apply relative pushand/or pull forces on the steering wires 30, controlling the directionand magnitude of the bending. Any combination of relative forces may beused. The entire handle 21 may be rotated by any amount to rotate thecatheter 12 and/or array 14. A shift in a bend plane may be provided byeither rotating the handle 21 or by changing the forces on the steeringwires 30. The motors 47, 48 may rotate AP and RL knobs 29, 40 to steerthe distal end of the catheter 12 in two different planes.

Rotation of the catheter handle 21 would cause rotation of the knobs 29,40 relative to their motors 47, 48 if the motors 47, 48 are notoperated. That is, the knob rotations became coupled with the whole-bodyrotation due to the knobs 29, 40 being locked to the motors 47, 48 bythe gearing. In one approach, the controller controls the motors 47, 48to rotate the knobs 29, 40 at a same rate as the rotation of the handle21 so that the relative rotation of the knobs 29, 40 to the handle 21 iszero. Due to the imprecise nature of a continuum manipulator such as ageneral catheter, it may be difficult to uncouple these degrees offreedom with the controller.

A mechanical decoupling is used. The motors 47, 48 are offset from theshafts 46, 58. The motor shafts are parallel but spaced from the shafts46, 58. For example, the motor shaft of motor 47 connects to the shaft46 through the gear 50. This offset allows for rotation of the motors47, 48 about the shafts 46, 58. The rotation of the entire motors 47, 48rotates the shafts 46, 58. The rate of rotation is set so that themechanical rotation imparted to the shafts 46, 58 by rotation of themotors 47, 48 about the shafts 46, 58 matches the handle rotation. Theknobs 29, 40 are mechanically rotated at a rate equal or similar to therotation of the handle 21.

In the embodiment of FIG. 3, the motors 47, 48 are positioned in acylindrical housing 49. The cylindrical housing 49 is metal, but plasticor other material may be used. In alternative embodiments, a ringsurrounds the motors 47, 48 without the housing (e.g., gear 56mechanically connects or links to the motors 47, 48 without thecylindrical housing 49).

The center axis of the cylindrical housing 49 aligns with or shares thesame longitudinal axis of the centers of the shafts 46, 58. The motors47, 48 are offset from this center axis. The cylindrical housing 49rotates, causing rotation of the motors 47, 48 about this center axis ofthe cylindrical housing. The cylindrical housing 49 is used tomechanically decouple the rotation of the catheter body 12 and therotation of the AP and RL knobs 29, 40. When the handle motor 53 causesa rotation of the handle 21, the cylindrical housing 49 containing theknob motors 47, 48 rotates as well. This rotation prevents relativerotations between the two knob motors 47, 48 and their respective knobgears 41, 42. Whether or not the handle motor 53 is rotating, the knobmotors 47, 48 are free to affect their respective knobs 29, 40.

A transmission in the base 34 rotates the cylindrical housing 49. Thetransmission is gearing, such as being three gears 54, 55, and 56 withmating teeth. Other gearing, such as rack-and-pinion, pulley and belt,or screw gears may be used. These or other types of gears may be usedfor any of the gearing, such as the gearing for transmission of forcefrom the motor 48 to the knob 29, from the motor 47 to the knob 40,and/or from the motor 53 to the handle 21.

The transmission for rotating the cylindrical housing 49 mechanicallydecouples actuation of the gear 43 from the gears 41, 42. When thehandle motor 53 causes a rotation, the housing containing the knobmotors 47, 48 rotates as well due to the transmission. This rotationprevents relative rotations between the two knob motors 47, 48 and theirrespective knob gears 41, 42. The rotation of the shaft 52 to rotate thehandle 21 also rotates the gear 54. The gear 54 rotates the gear 55about the shaft 57. The rotation of the gear 55 rotates the gear 56. Thegear 56 is mounted to the cylindrical housing 49 and/or the knob motors47, 48 so that the knob motors 47, 48 rotate with the gear 56. Inalternative embodiments, the gear 54 mates with the gear 56 without theintervening gear 55, or additional intervening gears are provided.

The rotation by the motor 53 causes the handle 21 to rotate and alsocauses the motors 47, 48 to rotate about a center axis of the shafts 46,58. The rotation of the catheter 12 about the longitudinal axis by thewhole body motor 53 rotates the knob motors 47, 48, causing rotation ofthe knobs 29, 40 in a same direction and rate as the handle 21. Rotationof the gear 54 causes rotation of the gear 56, which causes rotation ofthe cylindrical housing 49 so that the knob gears 41, 42 rotate,allowing the knobs 29, 40 to maintain position relative to the handle 21as the handle rotates.

This relative position is maintained while the motors 47, 48 are notactive. If the one or both knob motors 47, 48 activate during handlerotation, the rotation of the motors 47, 48 decouples the knob rotation,so that the knob 29, 40 rotates relative to the rotating handle 21 tosteer the catheter 12. The handle rotation rotates the steering plane.Within the steering plane, the knob rotation changes the bend of thecatheter 12. Whether or not the handle motor 53 is rotating the shaft52, the knob motors 47, 48 are free to affect their respective knobs 29,40 due to the transmission from gears 54, 55, and 56 with the motors 47,48 offset from the center of the shafts 46, 58. The knobs 29, 40 may berotated by the motor 53 through the transmission to maintain position,rotated by the knob motors 47, 48 to change the bend, or rotated by bothto account for handle rotation while also changing the bend.

FIG. 4 is a flow chart diagram of one embodiment of a method forrobotically operating a catheter. The method includes positioning andorienting the catheter for insertion into the patient and roboticcontrol of the position and orienting of the distal end of the catheterafter insertion. A base design provides for ease of positioning forinsertion and mechanical decoupling of handle rotation from knobrotation provides for ease of robotic control after insertion.

The method is implemented by the system and/or robotic system of FIGS. 2and 3 or another system. The method uses the ICE catheter and imagingsystem of FIG. 1 or a different catheter. The method is described belowusing the catheter 12 of FIG. 1 and the robotic system of FIGS. 2 and 3.

Additional, different, or fewer acts may be provided. For example, acts60-64 are not provided. As another example, act 68 is not provided. Inyet another example, act 70 is not provided.

The acts are performed in the order shown or a different order. In theexample of FIG. 6, acts 60-64 are performed to position for insertion,and acts 66-70 are performed for use as inserted. Act 70 may beperformed prior to or during acts 66 and 68. Acts 66 and 68 areperformed simultaneously. Act 62 may be performed prior to act 60 and/orafter act 64.

In act 60, the base 34 and arm 36 are positioned. The base 34 ispositioned relative to the patient. Depending on the point of access ofthe catheter 12 to the patient, the base 34 is positioned to align thecatheter 12 with the patient and point of access. FIG. 5 shows anexample where the base 34 is positioned for catheter 12 insertion intothe femoral artery. The base 34 is positioned on a table or bed betweenthe legs of the patient 70. The base 34 may be positioned relative tothe patient at other locations, such as for access for the radial orjugular.

The base 34 rests on the table. Alternatively, the base 34 is attachedto the table, such as by suction, magnetic, or mechanically (e.g., alatch or pin system).

The arm 36 is adjusted to place the access point housing 39 at theaccess point. A tip or exit location on the access point housing 39 ispositioned against or by the already inserted sheath at the access pointon the patient 70. The access point housing 39 is positioned by manualor robotic positioning of the arm 36. Upon desired positioning, the arm36 is locked in place by one or more brakes, such as activated by theknob 37.

In act 62, the catheter 12 is placed in the robotic system. The handle21 is placed in the handle housing 33. The handle housing 33 is closedaround the handle 21 and latched in place to hold the handle 21.

This positioning occurs while the catheter handle housing 33 connectswith the base 34. In one embodiment, the catheter handle housing 33 isseparable from the base 34. The handle 21 is positioned in the catheterhandle housing 33 while the catheter handle housing 33 is not attachedto the base.

A sterile bag may be placed around the catheter 12. One or more holesare provided in the sterile bag, such as for the catheter 12 to extendinto the patient and/or for the cable from the catheter handle 21 toconnect to an imaging system. In one embodiment, the entire roboticsystem other than power and/or control cables and catheter exit pointare placed in the sterile bag. In another embodiment, two holes areprovided in the sterile bag for the shafts 52 and 58. The base 34connects to the catheter handle housing 33 through a plastic interfacewith the two holes of the sterile bag. The catheter handle housing 33,the catheter 12, and the access point housing 39 are outside the sterilebag. The base 34, arm 36, and access point base 38 are in the sterilebag. Since all electronics are kept sterile by the bag, the electronicsmay be reused without cleaning or with a less intense cleaning. Sinceall parts not inside the bag are plastic or metal, these parts may beeasily cleaned in-house and reused as many times as the catheter 12 isreused.

The shaft housing 20 of the catheter 12 may be inserted into the accesspoint housing 39. The tip 32 of the catheter 12 is fed through anaperture of the access point housing 39. Alternatively, the access pointhousing 39 is a clam shell or has a removable side wall part to lay theshaft housing 20 in the access point housing 39. The insertion may feedthe catheter 12 into the patient, such as through an already placedsheath. The handle 21 may be placed in the catheter handle housing 33after or during insertion of the catheter shaft 20 through the accesspoint housing 39 and/or into the patient 70.

In act 64, the position of the handle housing 33 relative to the base 34may be adjusted. For example, the knobs 35 are activated or used toalter the position and/or orientation of the interface plate 59. Theplate 59 and corresponding motors 47, 48, and 53 may be translatedforwards or backwards and/or left or right. The plate 59 andcorresponding motors 47, 48, and 53 may be rotated clockwise or counterclockwise. The plate 59 and corresponding motors 47, 48, and 53 may beangled upward or downward.

Once the catheter 12 is positioned in the patient and in the roboticsystem, the robotic system may be used to steer the distal tip throughrotation of the catheter 12 and/or bending in one or more planes. Thedistal end and tip 32 are inserted into the patient 70. Any length ofcatheter 12 may be inserted. As the catheter 12 progresses into thepatient 70, the catheter 70 may bend and/or twist with the vessel intowhich the catheter 12 is inserted. Steering may guide the catheter 12,such as applying force to steering wires to bend the catheter toprogress in a given direction and/or rotating the handle 21.

The motors 47, 48, and 53 and motor drivers drive motions of the imagingdevice (e.g., array 14). While the catheter 12 is within the patient,the robotic system user may rotate the catheter 12. The catheter rotatesabout the longitudinal axis. For any bends caused by the vessel path,the catheter flexes to maintain the bend. For any bends caused bysteering (i.e., force applied by the steering wires 30), the catheter 12resists flexing to bend with the vessel. Where the bend is in a chamber,the rotation of the catheter 12 may not change the bend. The rotation ofthe catheter 12 would cause the plane of the bend to rotate.

The steering while the distal tip is within the patient 70 may beperformed robotically. In acts 66-70, a controller controls one or moreknob motors 47, 48 and the handle motor 53. Different knob motors 47, 48connect to different knobs 29, 40 for controlling what would otherwisebe manual steering with guide wires 30 using the knobs 29, 40. One ormore bends are formed by active control of force provided by the knobmotors 47, 48 in act 70. The orientation of the bending planes may berotated by the handle motor 53 rotating the handle in act 66.

In act 66, the controller activates the handle rotation motor 53. Thisrotates the gear 51, which rotates the gear 43. The gear 43 is linked tothe handle 21, such as through pressure contact or other mechanicallinkage. The rotation of the gears 51 and 43 causes the handle 21 of thecatheter 12 to rotate about a longitudinal axis of the handle 21.

In act 68, the rotation of the gear 43 and the handle 21 is transmittedto rotation of the knob gears 41, 42. The rotation of the gear 51, shaft51, and the handle 21 is transmitted to rotation of the gears 44, 45,shafts 46, 58, and the knobs 29, 40. The rotation is transmitted throughthe gears 54, 55, and 56. In the embodiment of FIG. 3, the cylindricalhousing 49 of the motors 47, 48 rotates due to the transmission. Theoff-center positioning of the motors 47, 48 causes rotation of the knobs29, 40 through the gearing.

This transmission causes knob rotation not powered by the knob motors47, 48, but instead powered by the handle motor 53. The transmittedrotation causes rotation of the knobs 29, 40 to match the rotation ofthe handle 21. By rotating the motors 47, 48 about the center of theshafts 46, 58, the knobs 29, 40 are rotated with the handle 21 despitebeing linked through gearing to the motors 47, 48. The motors 47, 48 maynot be activated so act as a brake, yet the transmitted rotation of themotors 47, 48 moves the gears 41, 42 to move the knobs 29, 40 to movewith the handle 21. Where the motors 47, 48 are activated during handlerotation, the extra rotation by the shafts of the motors 47, 48 causesextra rotation of the gears 41, 42, which alters the relative rotationof the knobs 29, 40 to the handle 21.

In act 70, one or more knobs 29, 40 are rotated to steer. The motor 47rotates the motor shaft, which rotates the gear 50. Rotation of the gear50 rotates the shaft 46, which rotates the gear 45. The rotation of thegear 45 rotates the gear 42, which rotates the knob 40, such as steeringin the anterior-posterior plane.

The motor 48 rotates the motor shaft, which rotates gear mated withgearing on the shaft 58. Rotation of the shaft 58 rotates the gear 44.The rotation of the gear 44 rotates the knob 29, such as steering inleft-right plane.

The knobs 29, 40 are rotated independently of each other and therotation of the handle 21. When the handle 21 is not being rotated, therotation of the gearing and knobs 29, 40 is not transmitted to thehandle 21. When the handle 21 is being rotated, the knobs 29, 40 rotatewith the handle 21 where the knobs 29, 40 are not activated to changesteering. Where the steering or bending is to change, the motors 47, 48cause the knobs 29, 40 to change position relative to the handle 21 evenif the handle 21 is rotating.

During steering and/or after positioning, the catheter 12 is used. Foran intervention catheter, drugs may be injected from the catheter 12 ora tool on the catheter 12 is used (e.g., scissors, needle, ablationelectrode, scalpel, or another instrument).

For the imaging catheter of FIG. 1, the transducer is used forultrasound scanning in a field of view. Ultrasound imaging is performedwith the transducer. The user may view the surrounding tissue indifferent directions by rotating the catheter and/or other steering.Changes in bending may alter the field of view to image other anatomy ordevices in the patient.

While the invention has been described above by reference to variousembodiments, it should be understood that many changes and modificationscan be made without departing from the scope of the invention. It istherefore intended that the foregoing detailed description be regardedas illustrative rather than limiting, and that it be understood that itis the following claims, including all equivalents, that are intended todefine the spirit and scope of this invention.

I (we) claim:
 1. A robotic catheter system comprising: a first motorconfigured by first gearing to rotate a catheter about a longitudinalaxis; a second motor configured by second gearing to rotate a first knobof a handle of the catheter; and third gearing connected between thefirst motor and the second motor so that the rotation of the catheterabout the longitudinal axis by the first motor rotates the second motorto rotate the first knob.
 2. The robotic catheter system of claim 1wherein the second motor is a servo motor.
 3. The robotic cathetersystem of claim 1 further comprising a catheter handle housing and abase housing, the first and second motors being in the base housing, andthe first and second gearing being in the catheter handle housing. 4.The robotic catheter system of claim 3 wherein the base housing is lessthan 16 inches long, 12 inches high, and 6 inches wide.
 5. The roboticcatheter system of claim 3 further comprising an arm connected with thebase, the arm being jointed and connected to an access point housingconfigured to hold the catheter away from the handle and at a point ofentry into a patient.
 6. The robotic catheter system of claim 3 whereinthe base housing has a second knob configured to adjust a position ofthe first and second motors relative to the base.
 7. The roboticcatheter system of claim 1 wherein the first knob comprises ananterior-posterior or a left-right knob for steering a distal end of thecatheter.
 8. The robotic catheter system of claim 1 wherein the firstknob is rotatable relative to the handle and about the longitudinalaxis, and wherein the third gearing is configured so that the first knobmaintains a position relative to the handle while the handle rotateswith the rotation of the catheter while the second motor is notactivated.
 9. The robotic catheter system of claim 1 wherein the firstgearing includes a first gear matable with a second gear, the secondgear extending around the handle so that rotation of the first gear bythe first motor causes rotation of the second gear about thelongitudinal axis.
 10. The robotic catheter system of claim 1 furthercomprising a cylindrical housing for the second motor, the third gearingincluding a gear with teeth around the cylindrical housing so thatrotation of the first motor rotates the cylindrical housing and thesecond motor.
 11. The robotic catheter system of claim 10 wherein thesecond motor is offset from a longitudinal center of the cylindricalhousing wherein the second gearing includes a first shaft at thelongitudinal center of the cylindrical housing so that the rotation ofthe cylindrical housing rotates the second motor about the longitudinalcenter.
 12. The robotic catheter system of claim 11 further comprising athird motor within the cylindrical housing and fourth gearing connectingthe third motor with a second knob of the handle, the fourth gearingincluding a second shaft at the longitudinal center of the cylindricalhousing, the first shaft nested and rotatable independently of thesecond shaft.
 13. A method for robotically operating a catheter, themethod comprising: rotating a first gear linked to the catheter so thatthe rotating of the first gear causes a handle of the catheter to rotateabout a longitudinal axis of the handle; and transmitting the rotationof the first gear to a second gear so that rotation of the second gearcauses rotation of a third gear linked to a knob of the handle.
 14. Themethod of claim 13 wherein rotating the first gear comprises rotatingthe first gear with a first motor, wherein a second motor is configuredto rotate the third gear, and wherein transmitting comprisestransmitting where the rotation of the third gear is from rotation ofthe second gear and not powered by the second motor.
 15. The method ofclaim 14 wherein transmitting comprises rotating a motor housing of thesecond motor where the second motor is mounted off-center in the motorhousing.
 16. The method of claim 14 further comprising rotating thethird gear by the second motor independently of the rotating of thefirst gear, the rotating the third gear not being transmitted to thefirst gear.
 17. The method of claim 13 further comprising: positioning abase relative to a patient; placing the handle in a handle housing wherethe first gear is within the handle housing and connects with the basethrough a motor shaft; and adjusting a position of the handle housingrelative to the base; wherein the rotating occurs after the adjusting.18. A system for guiding a catheter, the system comprising: a handlehousing configured to hold a handle of the catheter, the handle housinghaving a first gear to rotate the handle and a second gear to rotate afirst knob on the handle; a base connectable with the handle housing sothat the first and second gears are driven from the base; and an accesspoint housing configured to hold a shaft of the catheter away from thehandle, the access point housing configured to adjust an angle of theshaft relative to the handle.
 19. The system of claim 18 furthercomprising a transmission in the base mechanically decoupling actuationof the first gear from the second gear, wherein the transmissioncomprises a third gear on a first shaft with the first gear, the thirdgear linked to a fourth gear on a housing of a first motor linked to ashaft with the second gear so that rotation of the first gear causesrotation of the third gear, which causes rotation of the housing so thatthe second gear rotates, allowing the first knob to maintain positionrelative to the handle.
 20. The system of claim 19 further comprising afifth gear connected with and between the third gear and the fourthgear.
 21. The system of claim 18 further comprising an arm with one ormore joints connecting the base to the access point housing, wherein theaccess point housing includes one or more motors for adjusting theangle.